Attachment control selector



Aug. 6, 1968 s. T. COMFORT ATTACHMENT CONTROL SELECTOR 2 Sheets-SheekI 1 Filed May 25, 1966 W Z M @Mm/1M Aug' 6, 1968 s. T. COMFORT 3,395,732

ATTACHMENT CONTROL SELECTOR United States Patent O 3,395,732 ATTACHMENT CONTROL SELECTOR Samuel T. Comfort, Homewood, Ill., assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis. Filed May 25, 1966, Ser. No. 552,924 6 Claims. (Cl. 137-6362) This invention relates to a control system for a lmultiple function attachment such as used on lift trucks.

Heretofore separate valve levers and push button selection means have been provided for operator control of `multiple function lift truck attachments. Some prior art arrangements have required the operator to first manually select the function desired and then move his hand to the valve control lever to carry out the function selected. One prior art arrangement, shown in U.S. Patent 2,920,775, provides a single lever control for a multiple function lift truck attachment, however, such prior art construction is expensive, requires lan excessive number of parts and employs exposed actuating Switches, rendering the components relatively susceptible to deterioration and accidental damage. Another prior art arrangement is shown in my U.S. Patent 3,179,274 utilizing push button function selector switches. This arrangement employs electrical relays and holding circuits whereby once the push button selector switch is actuated the function is selected and movement of the control valve thereafter will perform the function selected. The difficulty with my prior arrangement is that the operator may forget which function he has previously selected and may unintentionally damage equipment, payload and personnel. For instance if the lift truck is equipped with a rotating, side shifting clamp and the operator thinks he has the rotating function selected when in fact he has the clamping function selected and decides to rotate the load while the lift truck is moving he may unintentionally release the load which, of course, would result in damage to the load and possibly injure personnel.

It is an object of the Kpresent invention to provide a control system for a multiple function attachment wherein the operator need not rely on memory or observation to select the proper function of the attachment.

It is a further object of this invention to provide a simple, inexpensive function selector means in a control system for a multiple function attachment.

It is a further object of this invention to provide a selector switch within the control knob of the control valve lever in a multiple function attachment control System.

It is a further object of this invention to provide a control system for a lmultiple function attachment utilizing a solenoid valve and an electrical control switch for such valve which is adequately protected from accidental damage and climatic conditions.

It is a further object of this invention to provide an improved single lever control for a multiple function attachment wherein the operator does not need to remove his hand from the control lever during operation of the attachment.

These and other objects and advantages of this invention will be apparent when the following description is read in conjunction with the drawings in which:

FIG. 1 is a schematic illustration of a control system for a multiple function attachment in which my invention is incorporated;

FIG. 2 is a side view of a lift truck employing a multiple function attachment and control system therefor;

FIG. 3 is a vertical section through the control lever for operating the control valve and incorporating features of this invention;

3,395,732 Patented Aug. 6, 1968 ice FIG. 4 is a section view taken along the line IV-IV in FIG. 3; and

FIG. 5 is a vertical section of a second version of a control knob which may be used in a control System of the present invention.

FIG. 1 shows schematically a control system for a multiple function attachment in which the present invention is utilized. The attachment 11 is mounted on a lift truck carriage 12 as shown in FIG. 2 which in turn is supported in a conventional manner on a lift truck mast 13. The dot-dash lines 14 in FIG. l enclose the portion of the multiple function attachment and control therefor which is mounted on the carriage 12. The attachment illustrated in FIGS. 1 and 2 is a rotating, side shifting clamp attachment wherein the clamp 16 (only one of which is shown) may be moved toward one another by retraction of hydraulic jacks 17, 18 and may be moved away from one another by expansion of jacks 17 and 18. The front portion of the attachment 11 may be rotated relative to the rear portion thereof about a longitudinal axis 19 by a hydraulic motor 21 in a Conventional manner.

The function performed by the attachment is determined by the position of a double solenoid selector valve 26. As illustrated, the selector valve 26 is in its neutral position in which the attachment may be rotated in either direction depending upon the position to which the control valve 27 is moved by control valve lever 28.

The selector valve 26, which is mounted on the nonrotatable part of the attachment 11, has a flow control component in the form of a spool 31 which is :axially shiftable from its illustrated neutral position in opposite axial directions by solenoids 32, 33, depending on which is energized. The double solenoid valve 26 and the attachment are similar to the construction shown in my U.S. Patent 3,179,274.

When the operator wishes to perform a clamping operation he rotates the knob part 36 of control lever 28 in one direction relative to its end part 37 a predetermined extent. This connects lead 38 to battery lead 39 thereby energizing solenoid 32 which -moves the spool 31 to the left as viewed in FIG. l. In this position of the spool 31, the operator may cause the arms 16 to close, that is to move toward one another, by pivoting the control lever 28 clockwise about its pivot 41 whereby fluid pressurized by pump 42 is supplied to the rod ends -lof jacks 17, 18. Counterclockwise adjustment of lever 28 will cause lcontrol valve spool 43 to be raised, thereby connecting the pump output to the closed ends of the jacks 17, 18 to cause the clamp arms 16 to be opened.

The knob part 36 as shown in FIGS, 3 and 4 has a top wall 46 and a side wall 47 which together with the end part 37 of lever 28 define an interior cavity 48 for receiving a three position toggle switch 51. A snap ring 57 maintains the parts 36, 37 in assembly. As shown in FIGS. 3 and 4 the toggle switch 51 has threaded engagement with a bracket 52 welded to the top wall 46 of knob part 36. When the knob part 36 is rotated in opposite directions from the illustrated clamp rotating position, abutment means in the form of pins 53, 54 will move actuating element 56 to clamping and side shifting function selection positions. The toggle switch 51 is a conventional, commercially available switch to which leads 38, 39, 40 are soldered. The switch 51 is relatively small in size and it may be possible for the operator to apply excessive force to the actuating element 56 unless means are provided to prevent same from occurring. I provide such a safeguard by provision of stop means including pins 61, 62 on knob part 36 which abut pins 53, 54 on end part 37 upon predetermined pivotal movement of the knob part 36 in either direction from its illustrated intermediate position.

In FIG. 5 I show a second embodiment of my novel control lever wherein the toggle switch 151 is secured to the end part 137 of a valve control lever 128 by a bracket 152 and the abutment means 153 are secured to the knob part 136. In this arrangement the leads to switch 151 are not subjected to scuffing action on pivoting the knob part.

By way of summary when the operator operates the control valve 27 with the knob part 36 in the position illustrated in FIG. 4, the front part of the clamp attachment 11 will be rotated in on direction or the other about a longitudinal pivot axis 19, depending on the direction of axial movement of control valve spool 43. When the control lever is moved from its illustrated hold position to operating positions with the knob part 36 pivoted in one direction, clamping and u-nclamping functions will be achieved. It the knob part 36 is rotated in the other direction from its intermediate position, a side shifting function may be performed, Incorporating a toggle switch for selecting the attachment function within the knob of the control lever 28 provides an inexpensive and reliable control which is considerably safer than prior art controls. The switch 51 is protected against accidental damage and is not subjected to rain or the like when the litt truck is outdoors. Indexing means in the form of a forward protrusion 81 may be formed on the knob part 36 so the operator may feel the rotated position of the knob part and hence be reminded of the function selected. The operator will quickly develop an unconscious sense of function selection` The embodiments of the invention for which an exclusive property or privilege is claimed are defined as follows:

1. In a control system for a multiple function material handling attachment having a plurality of fluid motors for operating same, the combination comprising:

control valve shiftable between neutral and attachment operating positions,

a manually operated control lever connected to said control valve having a knob part pivotally connected to an end part of said lever,

walls on said knob part dening an interior cavity,

an electrically operated selector valve shiftable to a plurality of control positions,

electric means controlling said selector valve including a control switch for said selector valve disposed within said cavity and secured to one of said parts, said switch including a switch actuating element shiftable between a plurality of control positions, and

abutment means on the other of said parts in confronting relation to said actuating element, said abutment means engaging said actuating element and shifting same upon said knob part being pivoted a predetermined extent relative to said end part.

2. The structure set forth in claim 1 wherein said one part is said knob part.

3. The srucure set forth in claim 1 wherein said one part is said end part.

4. The structure set forth in claim 1 and further comprising stop means formed on said parts limiting relative pivotal movement of said parts to prevent excessive force movement of said actuating element.

5. The structure set forth in claim 1 wherein said selector valve includes a ilow control component shiftable between three positions in which three different attachment functions are performable and wherein said switch has three operating positions corresponding to said three positions of said selector valve.

6. The structure set forth in claim 5 wherein said switch is a toggle switch.

References Cited UNITED STATES PATENTS 1,297,999 3/1919 Bryant 137-6363 X 2,450,481 lll/1948 May 137-6363 2,920,775 1/1960 Schenkelberger 214-653 3,179,274 4/1965 Comfort 214-652 3,180,514 4/1965 Horton 214-652 CLARENCE R. GORDON, Primary Examiner. 

1. IN A CONTROL SYSTEM FOR A MULTIPLE FUNCTION MATERIAL HANDLING ATTACHMENT HAVING A PLURALITY OF FLUID MOTORS FOR OPENING SAME, THE COMBINATION COMPRISING: CONTROL VALVE SHIFTABLE BETWEEN NEUTRAL AND ATTACHMENT OPERATING POSITIONS, A MANUALLY OPERATED CONTROL LEVER CONNECTED TO SAID CONTROL VALVE HAVING A KNOB PART PIVOTALLY CONNECTED TO AN END PART OF SAID LEVER, WALLS ON SAID KNOB PART DEFINING AN INTERIOR CAVITY, AN ELECTRICALLY OPERATED SELECTOR VALVE SHIFTABLE TO A PLURALITY OF CONTROL POSITIONS, ELECTRIC MEANS CONTROLLING SAID SELECTOR VALVE INCLUDING A CONTROL SWITCH FOR SAID SELECTOR VALVE DISPOSED WITHIN SAID CAVITY AND SECURED TO ONE OF SAID PARTS, SAID SWITCH INCLUDING A SWITCH ACTUATING ELEMENT SHIFTABLE BETWEEN A PLURALITY OF CONTROL POSITIONS, AND ABUTMENT MEANS ON THE OTHER OF SAID PARTS IN CONFRONTING RELATION TO SAID ACTUATING ELEMENT, SAID ABUTMENT MEANS ENGAGING SAID ACTUATING ELEMENT AND SHIFTING SAME UPON SAID KNOB PART BEING PIVOTED A PREDETERMINED EXTENT RELATIVE TO SAID END PART. 